Dry Dock to W of embanked Aqueduct

This dry dock and associated canal drain were constructed in 1805 as part of the Brecknock and Abergavenny Canal, under the direction of engineer Thomas Cartwright. The dry dock, a rectangular feature, is situated to the west of an embanked aqueduct. It was designed to be sealed off from the canal by stop planks, allowing water to drain into a stream via a trapezoidal-shaped sluice to the east. These elements are connected by a low bank constructed of rubble facing, although the dry dock itself has subsequently been repaired with a concrete facing. A footbridge spans the sluice. Two rack-and-pinion paddles remain to control the water levels of both the dock and the drain, and there was formerly a windlass used to operate a drain plug in the canal. A low rubble wall, continuing the parapet, extends beyond the sluice.

The Brecknock and Abergavenny Canal was initially promoted in 1792 to link the upper Usk valley with the Monmouthshire Canal, providing access to the sea at Newport. Construction began in 1797, and while the initial sections were completed by 1797 and 1800, work paused briefly. The stretch including the dry dock was not finished until 1805, with Thomas Cartwright taking over as engineer. Further construction continued and was completed between 1809 and 1812, under the direction of William Crosley. The canal facilitated the trade of iron, lime, and coal, being connected to tramroad networks. In 1865, the canal merged with the Monmouthshire Canal Company, and it was later acquired by the Great Western Railway. The canal gradually fell into disuse and was finally abandoned in 1962. Restoration work commenced in 1964 and remains ongoing.

The site is included on the register for its group value, contributing to the significance of the embanked aqueduct and other canal features as surviving elements of an early 19th century canal.